The present invention relates to a process for preparing a metal-containing supported catalyst or a supported catalyst component by impregnation of a support material.
The present invention also relates to a metal-containing supported catalyst or a metal-containing supported catalyst component obtainable by this process, a process for preparing polymers based on monomers having a Cxe2x80x94C double bond and/or Cxe2x80x94C triple bond, and also to the use of the metal-containing catalyst for forming carbon-carbon or carbon-heteroatom covalent bonds.
Supported catalysts are known and are widely used in many areas of industry. For example, they are used in processes for preparing low molecular weight organic chemicals and intermediates.
A further important application area for metal-containing supported catalysts is the preparation of polymers, in particular polyolefins and styrene polymers. Such polymerizations are preferably carried out in the gas phase or in suspension. The catalysts used are, for example, Ziegler catalysts or metallocene catalysts. For the purposes of the present invention, metallocene catalysts are catalysts comprising a metal complex, preferably a transition metal complex, bearing at least one ligand which in turn contains a cyclopentadienyl type structural unit. Examples of such bridged and unbridged ligands are substituted and unsubstituted cyclopentadienyl ligands, substituted and unsubstituted indenyl ligands or substituted or unsubstituted fluorenyl ligands. Metal complexes containing such ligands are known and are described, for example, in J. Macromol Scixe2x80x94Rev. Macromol Chem. Phys., C34, pages 439-514 (1994).
Processes for preparing metal-containing supported catalysts are known. Efforts are made here to ensure that
a) all suport particles are laden with the transition metal,
b) there are no differences in concentration of the metal component within the loaded support particles and
c) all particles have the same concentration of metal component (mg of metal/quantity of particle).
According to the present state of knowledge, such an ideal catalyst should be well suited, for example, to polymerizing olefins since it displays, inter alia, no sintering together of the polymer particles in the reactor (lump formation) and no. overheating of the catalyst particles resulting in deactivation of the catalyst.
According to a known method, supported metallocene catalysts can, for example, be obtained by combining a metallocene-containing solution with the support material, stirring the suspension and removing the solvent under reduced pressure (WO-A 94/28034). Here, the solution volume of the impregnation solution is much greater than the pore volume of the untreated support material, so that a readily stirrable suspension is obtained. Although the metallocene component can be completely applied to the support in this method, the catalyst leads, particularly at high loadings, to difficulties in the polymerization process, for example lump formation.
In a further process for applying metallocene catalysts to supports, the metallocene impregnation solution is combined with the support material with the volume of the impregnation solution being no more than the pore volume of the support material. This gives a paste-like mass from which the solvent is removed (WO-A 94/14856). A disadvantage of this process is that the loading of the support material with sparingly soluble metallocenes is unsatisfactory because of the small amount of solvent, the productivity of the catalyst is low and the economics of the polymerization process are still unsatisfactory.
In a third method of applying the catalyst to a support, the metallocene dissolved in a good solvent is precipitated by means of a poor solvent in the presence of the support material and thus precipitated on the surface of the support material and in its pores (EP-A 0 295 312, WO 98/01481). A disadvantage of this process is that large amounts of precipitation liquids (non-solvents) are required in order to deposit the metallocene component on and in the support material. For the preparation of catalysts, the advice given for industrial purposes is to restrict the amount of non-solvent, thereby leaving valuable metallocene component in solution and therefore losing it from the supported catalyst. This method is unsatisfactory in respect of the space-time yield of catalyst and the economics.
It is an object of the present invention to provide a more economical process for preparing metal-containing supported catalysts, in particular metallocene catalysts, which gives high space-time yields. The process should be universally applicable, i.e. metallocene complexes having very different solubilities, in particular relatively sparingly soluble metallocene complexes, should still lead to a high loading in the supported catalyst. Furthermore, the catalyst, in particular the metallocene catalyst, should have the metal component distributed over the volume of the support particles in such a way that it gives high catalyst productivities (g of polymer/g of catalyst solid) together with a good polymer morphology (virtually no formation of lumps and fines). In addition, an improved catalyst, improved polymerization processes and synthetic processes for low molecular weight organic compounds using the improved catalyst are to be made available.
We have found that this object is achieved by a process for preparing a metal-containing supported catalyst or a metal-containing supported catalyst component by impregnation of a support material with an impregnation solution comprising the metal component, wherein the impregnation solution flows through the support material, a metal-containing supported catalyst obtainable by this process, a process for preparing polymers based on monomers having a Cxe2x80x94C double bond and/or a Cxe2x80x94C triple bond by polymerization of these monomers in the presence of a metal-containing supported catalyst obtainable by the process of the present invention and the use of a metal-containing supported catalyst obtainable by the process of the present invention for forming carbon-carbon covalent bonds or carbon-heteroatom covalent bonds.
Possible metal components for the process or catalyst of the present invention are in principle all main group or transition metal compounds which are virtually completely soluble and/or finely dispersible in organic solvents or water or mixtures thereof.
Well suited main group metal compounds are, for example, halides, sulfates, nitrates, C1-C10-alkyls, C6-C20-aryls, C1-C10-alkoxides, C6-C20-aryloxides of metals or semimetals of the 1st to 5th main groups of the Periodic Table.
Well suited transition metal compounds are, for example, halides, sulfates, nitrates, C1-C10-alkyls, C6-C20-aryls, C1-C10-alkoxides, C6-C20-aryloxides of the transition metals.
Preference is given to using organometallic compounds of transition metals, for example compounds A), as metal component.
Well suited transition metal compounds A) are, for example: transition metal complexes including a ligand of the formulae F-I to F-IV 
where the transition metal is selected from among the elements Ti, Zr, Hf, Sc, V, Nb, Ta, Cr, Mo, W, Fe, Co, Ni, Pd, Pt or an element of the rare earth metals. Preference is given to compounds having nickel, iron, cobalt or palladium as central metal.
E is an element of group 15 of the Periodic Table of the Elements (5th main group), preferably N or P, particularly preferably N. The two atoms E in a molecule can be identical or different.
The radicals R1A to R19A, which can be identical or different, are the following groups:
Particularly useful compounds F-I to F-IV. are, for example:
di(2,6-di-i-propylphenyl)-2,3-dimethyldiazabutadienepalladium dichloride
di(di-i-propylphenyl)-2,3-dimethyldiazabutadienenickel dichloride
di(2,6-di-i-propylphenyl)dimethyldiazabutadiene(dimethyl)-palladium
di(2,6-di-i-propylphenyl)-2,3-dimethyldiazabutadiene(dimethyl)-nickel
di(2,6-dimethylphenyl)-2,3-dimethyldiazabutadienepalladium dichloride
di(2,6-dimethylphenyl)-2,3-dimethyldiazabutadienenickel dichloride
di(2,6-dimethylphenyl)-2,3-dimethyldiazabutadiene(dimethyl)-palladium
di(2,6-dimethylphenyl)-2,3-dimethyldiazabutadiene(dimethyl)-nickel
di(2-methylphenyl)-2,3-dimethyldiazabutadienepalladium dichloride
di(2-methylphenyl)-2,3-dimethyldiazabutadienenickel dichloride
di(2-methylphenyl)-2,3-dimethyldiazabutadiene(dimethyl)palladium
di(2-methylphenyl)-2,3-dimethyldiazabutadiene(dimethyl)nickel
diphenyl-2,3-dimethyldiazabutadienepalladium dichloride
diphenyl-2,3-dimethyldiazabutadienenickel dichloride
diphenyl-2,3-dimethyldiazabutadiene(dimethyl)palladium
diphenyl-2,3-dimethyldiazabutadiene(dimethyl)nickel
di(2,6-dimethylphenyl)azanaphthenepalladium dichloride
di(2,6-dimethylphenyl)azanaphthenenickel dichloride
di(2,6-dimethylphenyl)azanaphthene(dimethyl)palladium
di(2,6-dimethylphenyl)azanaphthene(dimethyl)nickel
1,1xe2x80x2-bipyridylpalladium dichloride
1,1xe2x80x2-bipyridylnickel dichloride
1,1xe2x80x2-bipyridyl(dimethyl)palladium
1,1xe2x80x2-bipyridyl(dimethyl)nickel
Particularly useful compounds F-V are those which are described in J. Am. Chem. Soc. 120, p. 4049 ff. (1998) and J. Chem. Soc., Chem. Commun. 1998, 849.
Further transition metal compounds A) which are particularly well suited are ones including at least one cyclopentadienyl type ligand, which are generally referred to as metallocene complexes (two or more cyclopentadienyl type ligands) or semisandwich complexes (one cyclopentadienyl type ligand). Particularly suitable complexes are those of the formula 
where the substitutents have the following meanings:
where the radicals
or the radicals R4 and Z together form an xe2x80x94R15xe2x80x94Axe2x80x94 group, where 
xe2x95x90BR16, xe2x95x90AlR16, xe2x80x94Gexe2x80x94, xe2x80x94Snxe2x80x94, xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x95x90SO, xe2x95x90SO2, xe2x95x90NR16, xe2x95x90CO, xe2x95x90PR16 or xe2x95x90P(O)R16, where
or the radicals R4 and R12 together form an xe2x80x94R15xe2x80x94 group.
Among the metallocene complexes of the formula I, preference is given to 
The radicals X can be identical or different; they are preferably identical.
Among the compounds of the formula Ia, particular preference is given to those in which
Among the compounds of the formula Ib, preference is given to those in which
Particularly useful compounds of the formula Ib are those in which the cyclopentadienyl radicals are identical.
Examples of particularly suitable compounds are:
bis(cyclopentadienyl)zirconium dichloride,
bis(pentamethylcyclopentadienyl)zirconium dichloride,
bis(methylcyclopentadienyl)zirconium dichloride,
bis(ethylcyclopentadienyl)zirconium dichloride,
bis(n-butylcyclopentadienyl)zirconium dichloride and
bis(trimethylsilylcyclopentadienyl)zirconium dichloride
and also the corresponding dimethylzirconium compounds.
Particularly suitable compounds of the formula Ic are those in which
Examples of particularly suitable complexes Ic are:
dimethylsilanediylbis(cyclopentadienyl)zirconium dichloride,
dimethylsilanediylbis(indenyl)zirconium dichloride,
dimethylsilanediylbis(tetrahydroindenyl)zirconium dichloride,
ethylenebis(cyclopentadienyl)zirconium dichloride,
ethylenebis(indenyl)zirconium dichloride,
ethylenebis(tetrahydroindenyl)zirconium dichloride,
tetramethylethylene-9-fluorenylcyclopentadienylzirconium dichloride,
dimethylsilanediylbis(3-tert-butyl-5-methylcyclopentadienyl)-zirconium dichloride,
dimethylsilanediylbis(3-tert-butyl-5-ethylcyclopentadienyl)-zirconium dichloride,
dimethylsilanediylbis(2-methylindenyl)zirconium dichloride,
dimethylsilanediylbis(2-isopropylindenyl)zirconium dichloride,
dimethylsilanediylbis(2-tert-butylindenyl)zirconium dichloride,
diethylsilanediylbis(2-methylindenyl)zirconium dibromide,
dimethylsilanediylbis(3-methyl-5-methylcyclopentadienyl)-zirconium dichloride,
dimethylsilanediylbis(3-ethyl-5-isopropylcyclopentadienyl)-zirconium dichloride,
dimethylsilanediylbis(2-ethylindenyl)zirconium dichloride,
dimethylsilanediylbis(2-methylbenzindenyl)zirconium dichloride,
dimethylsilanediylbis(2-ethylbenzindenyl)zirconium dichloride,
methylphenylsilanediylbis(2-ethylbenzindenyl)zirconium dichloride,
methylphenylsilanediylbis(2-methylbenzindenyl)zirconium dichloride,
diphenylsilanediylbis(2-methylbenzindenyl)zirconium dichloride,
diphenylsilanediylbis(2-ethylbenzindenyl)zirconium dichloride,
and diphenylsilanediylbis(2-methylindenyl)hafnium dichloride
and also the corresponding dimethylzirconium compounds.
Further examples of suitable complexes Ic are:
dimethylsilanediylbis(2-methyl-4-phenylindenyl)zirconium dichloride,
dimethylsilanediylbis(2-methyl-4-[1-naphthylindenyl])zirconium dichloride,
dimethylsilanediylbis(2-methyl-4-isopropylindenyl)zirconium dichloride,
dimethylsilanediylbis(2-methyl-4,6-diisopropylindenyl)zirconium dichloride,
dimethylsilanediylbis(2-ethyl-4-phenylindenyl)zirconium dichloride,
dimethylsilanediylbis(2-methyl-4-(para-4-butyl)phenylindenyl)-zirconium dichloride, and also the corresponding dimethylzirconium compounds.
Particularly suitable compounds of the formula Id are those in which 
Such complexes can be synthesized by methods known per se, with preference being given to reacting the appropriately substituted, cyclic hydrocarbon anions with halides of titanium, zirconium, hafnium, vanadium, niobium or tantalum.
Examples of appropriate methods are described, for example, in Journal of organometallic Chemistry, 369 (1989), 359-370.
It is also possible to use mixtures of various metal complexes A), in particular different metallocene complexes.
The impregnation solution is generally prepared by dissolving or suspending the metal component, preferably the transition metal component, in particular the metallocene complex I, and, if desired, other additives such as cocatalysts in water or preferably organic solvents. Those skilled in the art will know which metal components can be. combined with water and which can be combined with organic solvents.
Suitable organic solvents are all those in which the metal component is virtually completely soluble or soluble to an extent of at least 80% by weight. Well suited solvents are, for example, linear or cyclic, saturated, unsaturated or preferably aromatic hydrocarbons, halogenated C1-C20-hydrocarbons, C2-C20-ethers, C1-C20-alcohols or C2-C20-nitriles.
Well suited aromatic solvents are C6-C20-aromatics such as benzene, toluene, ethylbenzene, o-, m- or p-xylene, each of which may also be partially or fully substituted, for example by halogen atoms or alkyl radicals.
Further well suited solvents are C5-C20-aliphatic or alicylic hydrocarbons such as pentane, n-hexane, n-heptane, isododecne.
Examples of suitable C2-C20-ethers are diethyl ether, di-tert-butyl ether, diphenyl ether, 1,4-dioxane and THF Examples of well suited C1-C20-alcohols are methanol, ethanol, n-butanol, isopropanol, t-butanol and phenol.
It is also possible to use mixtures of the organic solvents.
In addition to the solvent, the impregnation solution can comprise the metal component as single significant component or else comprise the metal component and one or more additives such as compounds B) capable of forming metallocenium ions and/or organometallic compounds C).
The impregnation solution can comprise one or more different metal components A), preferably metallocene complexes I.
In the case of the transition metal compounds A), preferably the organometallic compounds of transition metals A), particularly in the case of the metallocene complexes I, the impregnation solution preferably further comprises compounds B) capable of forming metallocenium ions and/or organometallic compounds C) as additives.
The compounds B) capable of forming metallocenium ions are generally uncharged Lewis acids, ionic compounds containing strong Lewis-acid cations or Brxc3x6sted acids as cation, or aluminoxanes.
Strong, uncharged Lewis acids as component B) are compounds of the formula II
M3X1X2X3xe2x80x83xe2x80x83II
where
Particular preference is given to compounds of the formula II in which X1, X2 and X3 are identical, preferably tris(pentafluoro-phenyl)borane.
Ionic compounds as component B) which contain strong Lewis-acid cations are compounds of the formula III
[(Ya+)Q1Q2 . . . Qz]d+xe2x80x83xe2x80x83III
where
Particularly suitable Lewis-acid cations are carbonium cations, oxonium cations and sulfonium cations and also cationic transition metal complexes. Particular mention may be made of the triphenylmethyl cation, the silver cation and the 1,1xe2x80x2-dimethylferrocenyl cation. They preferably have noncoordinating counterions, in particular boron compounds as are mentioned in WO 91/09882, preferably tetrakis(pentafluorophenyl)-borate.
Ionic compounds as component B) which have Brxc3x6nsted acids as cations and preferably likewise noncoordinating counterions are mentioned in WO 91/09882; the preferred cation is N,N-dimethyl-anilinium.
The amount of compound capable of forming metallocenium ions is preferably from 0.1 to 10 equivalents, based on the transition metal component A).
The component B) can also be or include an aluminoxane. Particularly useful cation-forming compounds B) are open-chain or cyclic aluminoxane compounds of the formula V or VI 
where R24 is a C1-C4-alkyl group, preferably a methyl or ethyl group, and m is an integer from 5 to 30, preferably from 10 to 25.
The preparation of these oligomeric aluminoxane compounds is 30 customarily carried out by reacting a solution of trialkylaluminum with water and is described, for example, in EP-A 284 708 and U.S. Pat. No. 4,794,096.
In general, the oligomeric aluminoxane compounds obtained in this way are in the form of mixtures of both linear and cyclic chain molecules of various lengths, so that m is to be regarded as a mean. The aluminoxane compounds can also be present in admixture with other metal alkyls, preferably with aluminum alkyls.
It is also possible to use, as component B), aryloxyaluminoxanes as described in U.S. Pat. No. 5,391,793, aminoaluminoxanes as described in U.S. Pat. No. 5,371,260, aminoaluminoxane hydrochlorides as described in EP-A 633 264, siloxyaluminoxanes as described in EP-A 621 279 or mixtures thereof.
It has been found to be advantageous to use the transition metal compound A) and the oligomeric aluminoxane compound in such amounts that the atomic ratio of aluminum from the oligomeric aluminoxane compound to the transition metal from the transition metal compound A) is in the range from 1:1 to 106:1, preferably from 1:1 to 104:1, in particular in the range from 1:1 to 103:1.
The catalyst system of the present invention can, if desired, further comprise an organometallic compound as component C), preferably a metal compound of the formula IV
M1(R21)r(R22)s(R23)txe2x80x83xe2x80x83IV
where
If the component C) is present together with A) and/or B), it is not identical to the components A) and, in particular, B).
Among the metal compounds of the formula IV, preference is given to those in which
M1 is lithium, magnesium or aluminum and
R21 to R23 are C1-C10-alkyl.
Particularly preferred metal compounds of the formula IV are n-butyllithium, n-butyl-n-octylmagnesium, n-butyl-n-heptyl-magnesium, tri-n-hexylaluminum, triisobutylaluminum, triethylaluminum and trimethylaluminum.
If a component C) is used, it is preferably present in the catalyst system in an amount of from 800:1 to 1:1, in particular from 500:1 to 50:1 (molar ratio of M1 from IV to transition metal M from I).
If the impregnation solution comprises, apart from the solvent, only the metal component A) as significant component, the supported catalyst component according to the present invention is generally isolated first and then, either in the presence of the substrates to be reacted, e.g. monomers, or in their absence, activated by addition of the components B) and/or C).
Support materials used in the catalyst system of the present invention are preferably finely divided supports which have a particle diameter in the range from 0. 1 to 1000 xcexcm, preferably from 10 to 300 xcexcm, in particular from 30 to 70 xcexcm. Suitable organic supports are, for example, finely divided polymers, e.g. finely divided polyethylene or finely divided polypropylene. Suitable inorganic supports are, for example, aluminum oxide, silicon dioxide, titanium dioxide or their mixed oxides, aluminum phosphate or magnesium chloride. Preference is given to using silica gels of the formula SiO2.a Al2O3, where a is from 0 to 2, preferably from 0 to 0.5. The support particles can be used in granular form or in spray-dried, microscopic form. Such products are commercially available, e.g. silica gel 332 from Grace or ES 70 X from Crosfield.
Preferred inorganic support materials are acid, inorganic metal or semimetal oxides having a very high porosity, as are described, for example, in the earlier German Patent Application 197 20 980.7, in particular on page 3, line 45 to page 5, line 11.
The support materials can have been pretreated thermally or chemically (e.g. with metal alkyl compounds) in order to achieve a certain property profile of the support (e.g. water content and/or OH group content).
The pore volume of the support materials used is generally in the range from 0.1 ml/g to 10.0 ml/g, preferably in the range from 0.5 ml/g to 3.0 ml/g. The pore volume can be determined by the method of nitrogen adsorption in accordance with DIN 66131 or mercury porosimetry in accordance with DIN 66133.
The support substances can be thermally dried by baking out at temperatures in the range from 50 to 1200xc2x0 C., preferably in the range from 80 to 800xc2x0 C. They can additionally or alternatively be pretreated chemically by allowing organometallic compounds of the formula IV, in particular tri-C1-C4-alkylaluminums such as triisobutylaluminum, and/or aluminoxanes of the formula V and/or VI to act on them.
Preference is given to using silica gels having the defined parameters as support materials.
In the impregnation process of the present invention, the impregnation solution, whose composition has been described above, flows in a directed stream through the support material particles, likewise described above. There is not only flow between the individual support particles, but also flow through the particles. This improves mass transfer from the impregnation solution to the internal surface of the support material.
In contrast, according to the present state of knowledge, the impregnation solution in the prior art impregnation methods described at the outset penetrates uniformly into the particle from all sides, leading to the formation of concentration gradients.
The impregnation process of the present invention can be carried out in different variants. A generally column-shaped or cylindrical or tubular reaction vessel with inlet and outlet devices, comparable to a chromatography column, is filled to a certain height with the support material.
In each variant A) to C), the impregnated catalyst can, preferably after no more solvent runs out, be left to stand for from 0.1 to 100 hours, preferably from 0.5 to 24 hours, while, according to the present state of knowledge, the pore volume is still filled with the impregnation solution.
The impregnation solution generally flows through the support material under its own pressure. However, it is also possible to allow a pressure in the range from 1 to 1000 mbar to act on the liquid column of impregnation solution. The flow rate of the impregnation solution is generally in the range from 0.1 to 100.0 ml/(g of support materialxc3x97h), preferably in the range
from 1.0 to 50.0 ml/(g of support materialxc3x97h).
In general, the catalyst or the catalyst precursor is washed by rinsing with one or more low-boiling solvents. Preference is here given to solvents or solvent mixtures in which the metallocene or metallocenes and/or the additives B) and/or C) are less soluble than in the impregnation solution. The catalyst or the catalyst precursor is subsequently discharged as a suspension or dried using customary methods such as application of a vacuum or passing through an inert gas such as nitrogen. It is then obtained in free-flowing form.
In general, the volume of the impregnation solution is at least 1.5 times the pore volume of the chemically untreated support used. The volume of the impregnation solution is preferbaly from three to 10 times the pore volume of the chemically untreated support. The pore volume can be measured by the method of nitrogen adsorption (DIN 66131) or mercury porosimetry (DIN 66133).
As support material, it is also possible to use a Ziegler catalyst solid, usually based on titanium, or a Phillips catalyst, usually based on Cr. Such catalysts are described, for example, in Angew. Chemie 92, 869-87 (1980); EP-A 45975; EP-A 45977; EP-A 86473; EP-A 171200; EP-A 429937; DE-A 4132894; GB-A 2111066; U.S. Pat. Nos. 4,220,554; 4,339,054; 4,472,524; 4,473,660; 4,857,613. If a Ziegler or Phillips catalyst solid is used as support material, the process of the present invention gives a multicenter catalyst in which chemically different metals or metal complex fragments are present.
In the impregnation process of the present invention, the entire impregnation solution is, if desired using the variants A, B or C mentioned, allowed to flow through the support material and the catalyst is isolated. The eluted solvent or the impregnation solution depleted in components A) to C) can be used further. In the impregnation solution depleted in the components A) to C), the original concentration of the components A) to C) can be restored, for example by addition of the components or by partial evaporation of the solution (recycling). This impregnation solution can then be reused for the impregnation.
This process can be carried out continuously, but preferably batchwise.
The supported catalysts or supported catalyst components obtainable by the process of the present invention have a different loading level of the individual support particles, but virtually no unladen support particles can be detected. Here, the loading level is the concentration of the metal component used according to the present invention in the individual support particles. This means that the supported catalysts or the supported catalyst components obtainable are usually made up of fractions of supported catalyst particles or supported catalyst component particles which have a significantly different metal component content.
This phenomenon is referred to as loading level distribution in the following.
It is surprising that such a xe2x80x9cheterogeneousxe2x80x9d (based on the metal component concentration of the fractions) supported catalyst or supported catalyst component displays good process utility, for example in polymerization processes.
Both the integrated loading level, i.e. the sum of the metal components applied to the support material used, and the loading level distribution can be adjusted within wide limits by means of the starting concentration of metal component and any additives used in the impregnation solution, the volume of impregnation solution used and the choice of the solvent.
To analyze the loading level distribution, cf. Examples 10 and 11, the loading level of the catalyst particles is first measured at various points along the flow distance of the impregnation solution. For an empirically selected function of the type f(x)=a exp(xe2x88x92bx)+c (where x: flow distance; f(x): loading level in xcexc mol of metallocene (or metal component)/g of catalyst), the coefficients a, b and c which give the best fit of the function to the measured points are determined. Transformation and normalization of this mathematical relationship between loading level and flow distance for the supported catalyst gives a distribution function P(x) for the loading level (x: loading level) of the type P(x)=xcex1ln (xxe2x88x92c) [xcex1: normalization coefficient] and, by differentiation, the corresponding (probability) density function p(x)=xcex1/(xxe2x88x92c). This density function can then be used to determine the 1st moment (arithmetic means) xcexc1 of the loading level distribution,
For this purpose, the integrals were calculated numerically by the trapezoidal rule (steps: 1/10,000 of the total interval).
Preferred metal-containing supported catalysts have an asymmetric loading level distribution. Their loading level distribution has a standard deviation of at least 1% of the 1st moment of the distribution, and a skewness s which fulfills the condition s2 greater than 0.0001. Particularly preferred metal-containing supported catalysts fulfill the condition s greater than +0.01.
The supported catalysts obtainable by the process of the present invention can also be prepolymerized.
It is surprising that such a xe2x80x9cheterogeneousxe2x80x9d (based on the metal component concentration of the fractions) supported catalyst or supported catalyst. component displays good utility in processes, for example in polymerization processes.
The catalyst system of the present invention is generally used for the polymerization of monomers having a Cxe2x80x94C double bond or Cxe2x80x94C triple bond. The Cxe2x80x94C double bond or the Cxe2x80x94C triple bond or both can be terminal or internal, either exocyclic or endocyclic. Preferred monomers having a Cxe2x80x94C triple bond are C2-C10-alk-1-ynes, such as ethyne, propyne, 1-butyne, 1-hexyne and also phenylacetylene. The polymerization process of the present invention is preferably used for the polymerization or copolymerization of C2-C12-alk-1-enes. As C2-C12-alk-1-enes, preference is given to ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene or 1-octene or vinylaromatic monomers such as styrene, p-methylstyrene or 2,4-dimethylstyrene or mixtures of these C2-C12-alk-1-enes. Particular preference is given to homopolymers or copolymers of ethylene or of propylene, where the. proportion of ethylene or of propylene in the copolymers is at least 50 mol %. Among the copolymers of ethylene, preference is given to those in which propylene, 1-butene, 1-hexene or 1-octene or mixtures thereof are present as further monomers. The copolymers of propylene are, in particular, copolymers in which ethylene or 1-butene or mixtures thereof are present as further monomers.
The polymerization process of the present invention is preferably used for preparing polymers consisting of
from 50 to 100 mol % of ethylene and
from 0 to 50 mol %, in particular from 0 to 30 mol % of C3-C12-alk-1-enes.
Preference is also given to polymers consisting of
from 50 to 100 mol % of propylene,
from 0 to 50 mol %, in particular from 0 to 30 mol %, of ethylene and
from 0 to 20 mol %, in particular from 0 to 10 mol %, of C4-C12-alk-1-enes.
The sum of the mol % is always 100.
The polymerization can be carried out in the processes customary for the polymerization of olefins, for example solution processes, suspension processes, stirred gas-phase processes or gas-phase fluidized-bed processses, continuously or batchwise. Solvents or suspension media which can be used are inert hydrocarbons, for example isobutane, or else the monomers themselves. Particularly well suited methods of preparing the polymers are the suspension process and the gas-phase process (stirred gas phase, gas-phased fluidized bed).
Suitable reactors are, for example, continuously operated stirred vessels, loop reactors or fluidized-bed reactors; if desired, it is also possible to use a plurality of reactors connected in series (reactor cascade).
The polymerization using the process of the present invention is generally carried out at from xe2x88x9250 to 300xc2x0 C., preferably from 0 to 150xc2x0 C., and at pressures generally in the range from 0.5 to 3000 bar, preferably in the range from 1 to 80 bar. In the polymerization process of the present invention, it is advantageous to set the residence times of the respective reaction mixtures to from 0.5 to 5 hours, in particular from 0.7 to 3.5 hours. It is also possible to use, inter alia, antistatics and molecular weight regulators, for example hydrogen, in the polymerization.
Apart from polymerisation, the catalyst system of the present invention can also be used for stoichiometric or catalytic carbon-carbon linkage, also for the reduction of carbonyl groups  greater than Cxe2x95x90O, or imino groups  greater than Cxe2x95x90NH with carbon radicals, hydrides or amides and also in the Diels-Alder reaction and the hydrogenation of unsaturated carbon-carbon, carbon-heteroatom or heteroatom-heteroatom bonds using hydrogen and/or hydrides.
In general, these reactions occur in the low molecular weight range and generally lead to products having a molecular weight of less than about 1000.
The polymers obtainable using the polymerization process of the present invention can be used for producing films, fibers and moldings.